/*
 * EAP peer: EAP-TLS/PEAP  TLS/FAST common functions
 * Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "eap_i.h"
#include "eap_tls_common.h"
#include "eap_config.h"
#include "sha1.h"
#include "tls.h"


static int eap_tls_check_blob(struct eap_sm *sm, const char **name,
                              const u8 **data, size_t *data_len)
{
        const struct wpa_config_blob *blob;

        if (*name == NULL || os_strncmp(*name, "blob://", 7) != 0)
                return 0;

        blob = eap_get_config_blob(sm, *name + 7);
        if (blob == NULL) {
                wpa_printf(MSG_ERROR, "%s: Named configuration blob '%s' not "
                           "found", __func__, *name + 7);
                return -1;
        }

        *name = NULL;
        *data = blob->data;
        *data_len = blob->len;

        return 0;
}


static void eap_tls_params_flags(struct tls_connection_params *params,
                                 const char *txt)
{
        if (txt == NULL)
                return;
        if (os_strstr(txt, "tls_allow_md5=1"))
                params->flags |= TLS_CONN_ALLOW_SIGN_RSA_MD5;
        if (os_strstr(txt, "tls_disable_time_checks=1"))
                params->flags |= TLS_CONN_DISABLE_TIME_CHECKS;
}


static void eap_tls_params_from_conf1(struct tls_connection_params *params,
                                      struct eap_peer_config *config)
{
        params->ca_cert = (char *) config->ca_cert;
        params->ca_path = (char *) config->ca_path;
        params->client_cert = (char *) config->client_cert;
        params->private_key = (char *) config->private_key;
        params->private_key_passwd = (char *) config->private_key_passwd;
        params->dh_file = (char *) config->dh_file;
        params->subject_match = (char *) config->subject_match;
        params->altsubject_match = (char *) config->altsubject_match;
        params->engine = config->engine;
        params->engine_id = config->engine_id;
        params->pin = config->pin;
        params->key_id = config->key_id;
        params->cert_id = config->cert_id;
        params->ca_cert_id = config->ca_cert_id;
        eap_tls_params_flags(params, config->phase1);
}


static void eap_tls_params_from_conf2(struct tls_connection_params *params,
                                      struct eap_peer_config *config)
{
        params->ca_cert = (char *) config->ca_cert2;
        params->ca_path = (char *) config->ca_path2;
        params->client_cert = (char *) config->client_cert2;
        params->private_key = (char *) config->private_key2;
        params->private_key_passwd = (char *) config->private_key2_passwd;
        params->dh_file = (char *) config->dh_file2;
        params->subject_match = (char *) config->subject_match2;
        params->altsubject_match = (char *) config->altsubject_match2;
        params->engine = config->engine2;
        params->engine_id = config->engine2_id;
        params->pin = config->pin2;
        params->key_id = config->key2_id;
        params->cert_id = config->cert2_id;
        params->ca_cert_id = config->ca_cert2_id;
        eap_tls_params_flags(params, config->phase2);
}


static int eap_tls_params_from_conf(struct eap_sm *sm,
                                    struct eap_ssl_data *data,
                                    struct tls_connection_params *params,
                                    struct eap_peer_config *config, int phase2)
{
        os_memset(params, 0, sizeof(*params));
        if (phase2) {
                wpa_printf(MSG_DEBUG, "TLS: using phase2 config options");
                eap_tls_params_from_conf2(params, config);
        } else {
                wpa_printf(MSG_DEBUG, "TLS: using phase1 config options");
                eap_tls_params_from_conf1(params, config);
        }
        params->tls_ia = data->tls_ia;

        /*
         * Use blob data, if available. Otherwise, leave reference to external
         * file as-is.
         */
        if (eap_tls_check_blob(sm, &params->ca_cert, &params->ca_cert_blob,
                               &params->ca_cert_blob_len) ||
            eap_tls_check_blob(sm, &params->client_cert,
                               &params->client_cert_blob,
                               &params->client_cert_blob_len) ||
            eap_tls_check_blob(sm, &params->private_key,
                               &params->private_key_blob,
                               &params->private_key_blob_len) ||
            eap_tls_check_blob(sm, &params->dh_file, &params->dh_blob,
                               &params->dh_blob_len)) {
                wpa_printf(MSG_INFO, "SSL: Failed to get configuration blobs");
                return -1;
        }

        return 0;
}


static int eap_tls_init_connection(struct eap_sm *sm,
                                   struct eap_ssl_data *data,
                                   struct eap_peer_config *config,
                                   struct tls_connection_params *params)
{
        int res;

        data->conn = tls_connection_init(sm->ssl_ctx);
        if (data->conn == NULL) {
                wpa_printf(MSG_INFO, "SSL: Failed to initialize new TLS "
                           "connection");
                return -1;
        }

        res = tls_connection_set_params(sm->ssl_ctx, data->conn, params);
        if (res == TLS_SET_PARAMS_ENGINE_PRV_INIT_FAILED) {
                /*
                 * At this point with the pkcs11 engine the PIN might be wrong.
                 * We reset the PIN in the configuration to be sure to not use
                 * it again and the calling function must request a new one.
                 */
                os_free(config->pin);
                config->pin = NULL;
        } else if (res == TLS_SET_PARAMS_ENGINE_PRV_VERIFY_FAILED) {
                wpa_printf(MSG_INFO, "TLS: Failed to load private key");
                /*
                 * We do not know exactly but maybe the PIN was wrong,
                 * so ask for a new one.
                 */
                os_free(config->pin);
                config->pin = NULL;
                eap_sm_request_pin(sm);
                sm->ignore = TRUE;
                return -1;
        } else if (res) {
                wpa_printf(MSG_INFO, "TLS: Failed to set TLS connection "
                           "parameters");
                return -1;
        }

        return 0;
}


/**
 * eap_peer_tls_ssl_init - Initialize shared TLS functionality
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * @config: Pointer to the network configuration
 * Returns: 0 on success, -1 on failure
 *
 * This function is used to initialize shared TLS functionality for EAP-TLS,
 * EAP-PEAP, EAP-TTLS, and EAP-FAST.
 */
int eap_peer_tls_ssl_init(struct eap_sm *sm, struct eap_ssl_data *data,
                          struct eap_peer_config *config)
{
        struct tls_connection_params params;

        if (config == NULL)
                return -1;

        data->eap = sm;
        data->phase2 = sm->init_phase2;
        if (eap_tls_params_from_conf(sm, data, &params, config, data->phase2) <
            0)
                return -1;

        if (eap_tls_init_connection(sm, data, config, &params) < 0)
                return -1;

        data->tls_out_limit = config->fragment_size;
        if (data->phase2) {
                /* Limit the fragment size in the inner TLS authentication
                 * since the outer authentication with EAP-PEAP does not yet
                 * support fragmentation */
                if (data->tls_out_limit > 100)
                        data->tls_out_limit -= 100;
        }

        if (config->phase1 &&
            os_strstr(config->phase1, "include_tls_length=1")) {
                wpa_printf(MSG_DEBUG, "TLS: Include TLS Message Length in "
                           "unfragmented packets");
                data->include_tls_length = 1;
        }

        return 0;
}


/**
 * eap_peer_tls_ssl_deinit - Deinitialize shared TLS functionality
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 *
 * This function deinitializes shared TLS functionality that was initialized
 * with eap_peer_tls_ssl_init().
 */
void eap_peer_tls_ssl_deinit(struct eap_sm *sm, struct eap_ssl_data *data)
{
        tls_connection_deinit(sm->ssl_ctx, data->conn);
        eap_peer_tls_reset_input(data);
        eap_peer_tls_reset_output(data);
}


/**
 * eap_peer_tls_derive_key - Derive a key based on TLS session data
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * @label: Label string for deriving the keys, e.g., "client EAP encryption"
 * @len: Length of the key material to generate (usually 64 for MSK)
 * Returns: Pointer to allocated key on success or %NULL on failure
 *
 * This function uses TLS-PRF to generate pseudo-random data based on the TLS
 * session data (client/server random and master key). Each key type may use a
 * different label to bind the key usage into the generated material.
 *
 * The caller is responsible for freeing the returned buffer.
 */
u8 * eap_peer_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
                             const char *label, size_t len)
{
        struct tls_keys keys;
        u8 *rnd = NULL, *out;

        out = os_malloc(len);
        if (out == NULL)
                return NULL;

        /* First, try to use TLS library function for PRF, if available. */
        if (tls_connection_prf(sm->ssl_ctx, data->conn, label, 0, out, len) ==
            0)
                return out;

        /*
         * TLS library did not support key generation, so get the needed TLS
         * session parameters and use an internal implementation of TLS PRF to
         * derive the key.
         */
        if (tls_connection_get_keys(sm->ssl_ctx, data->conn, &keys))
                goto fail;

        if (keys.client_random == NULL || keys.server_random == NULL ||
            keys.master_key == NULL)
                goto fail;

        rnd = os_malloc(keys.client_random_len + keys.server_random_len);
        if (rnd == NULL)
                goto fail;
        os_memcpy(rnd, keys.client_random, keys.client_random_len);
        os_memcpy(rnd + keys.client_random_len, keys.server_random,
                  keys.server_random_len);

        if (tls_prf(keys.master_key, keys.master_key_len,
                    label, rnd, keys.client_random_len +
                    keys.server_random_len, out, len))
                goto fail;

        os_free(rnd);
        return out;

fail:
        os_free(out);
        os_free(rnd);
        return NULL;
}


/**
 * eap_peer_tls_reassemble_fragment - Reassemble a received fragment
 * @data: Data for TLS processing
 * @in_data: Next incoming TLS segment
 * @in_len: Length of in_data
 * Returns: 0 on success, 1 if more data is needed for the full message, or
 * -1 on error
 */
static int eap_peer_tls_reassemble_fragment(struct eap_ssl_data *data,
                                            const u8 *in_data, size_t in_len)
{
        u8 *buf;

        if (data->tls_in_len + in_len == 0) {
                /* No message data received?! */
                wpa_printf(MSG_WARNING, "SSL: Invalid reassembly state: "
                           "tls_in_left=%lu tls_in_len=%lu in_len=%lu",
                           (unsigned long) data->tls_in_left,
                           (unsigned long) data->tls_in_len,
                           (unsigned long) in_len);
                eap_peer_tls_reset_input(data);
                return -1;
        }

        if (data->tls_in_len + in_len > 65536) {
                /*
                 * Limit length to avoid rogue servers from causing large
                 * memory allocations.
                 */
                wpa_printf(MSG_INFO, "SSL: Too long TLS fragment (size over "
                           "64 kB)");
                eap_peer_tls_reset_input(data);
                return -1;
        }

        if (in_len > data->tls_in_left) {
                /* Sender is doing something odd - reject message */
                wpa_printf(MSG_INFO, "SSL: more data than TLS message length "
                           "indicated");
                eap_peer_tls_reset_input(data);
                return -1;
        }

        buf = os_realloc(data->tls_in, data->tls_in_len + in_len);
        if (buf == NULL) {
                wpa_printf(MSG_INFO, "SSL: Could not allocate memory for TLS "
                           "data");
                eap_peer_tls_reset_input(data);
                return -1;
        }
        os_memcpy(buf + data->tls_in_len, in_data, in_len);
        data->tls_in = buf;
        data->tls_in_len += in_len;
        data->tls_in_left -= in_len;

        if (data->tls_in_left > 0) {
                wpa_printf(MSG_DEBUG, "SSL: Need %lu bytes more input "
                           "data", (unsigned long) data->tls_in_left);
                return 1;
        }

        return 0;
}


/**
 * eap_peer_tls_data_reassemble - Reassemble TLS data
 * @data: Data for TLS processing
 * @in_data: Next incoming TLS segment
 * @in_len: Length of in_data
 * @out_len: Variable for returning length of the reassembled message
 * @need_more_input: Variable for returning whether more input data is needed
 * to reassemble this TLS packet
 * Returns: Pointer to output data, %NULL on error or when more data is needed
 * for the full message (in which case, *need_more_input is also set to 1).
 *
 * This function reassembles TLS fragments. Caller must not free the returned
 * data buffer since an internal pointer to it is maintained.
 */
const u8 * eap_peer_tls_data_reassemble(
        struct eap_ssl_data *data, const u8 *in_data, size_t in_len,
        size_t *out_len, int *need_more_input)
{
        *need_more_input = 0;

        if (data->tls_in_left > in_len || data->tls_in) {
                /* Message has fragments */
                int res = eap_peer_tls_reassemble_fragment(data, in_data,
                                                           in_len);
                if (res) {
                        if (res == 1)
                                *need_more_input = 1;
                        return NULL;
                }

                /* Message is now fully reassembled. */
        } else {
                /* No fragments in this message, so just make a copy of it. */
                data->tls_in_left = 0;
                data->tls_in = os_malloc(in_len ? in_len : 1);
                if (data->tls_in == NULL)
                        return NULL;
                os_memcpy(data->tls_in, in_data, in_len);
                data->tls_in_len = in_len;
        }

        *out_len = data->tls_in_len;
        return data->tls_in;
}


/**
 * eap_tls_process_input - Process incoming TLS message
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * @in_data: Message received from the server
 * @in_len: Length of in_data
 * @out_data: Buffer for returning a pointer to application data (if available)
 * Returns: 0 on success, 1 if more input data is needed, 2 if application data
 * is available, -1 on failure
 */
static int eap_tls_process_input(struct eap_sm *sm, struct eap_ssl_data *data,
                                 const u8 *in_data, size_t in_len,
                                 struct wpabuf **out_data)
{
        const u8 *msg;
        size_t msg_len;
        int need_more_input;
        u8 *appl_data;
        size_t appl_data_len;

        msg = eap_peer_tls_data_reassemble(data, in_data, in_len,
                                           &msg_len, &need_more_input);
        if (msg == NULL)
                return need_more_input ? 1 : -1;

        /* Full TLS message reassembled - continue handshake processing */
        if (data->tls_out) {
                /* This should not happen.. */
                wpa_printf(MSG_INFO, "SSL: eap_tls_process_input - pending "
                           "tls_out data even though tls_out_len = 0");
                os_free(data->tls_out);
                WPA_ASSERT(data->tls_out == NULL);
        }
        appl_data = NULL;
        data->tls_out = tls_connection_handshake(sm->ssl_ctx, data->conn,
                                                 msg, msg_len,
                                                 &data->tls_out_len,
                                                 &appl_data, &appl_data_len);

        eap_peer_tls_reset_input(data);

        if (appl_data &&
            tls_connection_established(sm->ssl_ctx, data->conn) &&
            !tls_connection_get_failed(sm->ssl_ctx, data->conn)) {
                wpa_hexdump_key(MSG_MSGDUMP, "SSL: Application data",
                                appl_data, appl_data_len);
                *out_data = wpabuf_alloc_ext_data(appl_data, appl_data_len);
                if (*out_data == NULL) {
                        os_free(appl_data);
                        return -1;
                }
                return 2;
        }

        os_free(appl_data);

        return 0;
}


/**
 * eap_tls_process_output - Process outgoing TLS message
 * @data: Data for TLS processing
 * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
 * @peap_version: Version number for EAP-PEAP  TLS
 * @id: EAP identifier for the response
 * @ret: Return value to use on success
 * @out_data: Buffer for returning the allocated output buffer
 * Returns: ret (0 or 1) on success, -1 on failure
 */
static int eap_tls_process_output(struct eap_ssl_data *data, EapType eap_type,
                                  int peap_version, u8 id, int ret,
                                  struct wpabuf **out_data)
{
        size_t len;
        u8 *flags;
        int more_fragments, length_included;
        
        len = data->tls_out_len - data->tls_out_pos;
        wpa_printf(MSG_DEBUG, "SSL: %lu bytes left to be sent out (of total "
                   "%lu bytes)",
                   (unsigned long) len, (unsigned long) data->tls_out_len);

        /*
         * Limit outgoing message to the configured maximum size. Fragment
         * message if needed.
         */
        if (len > data->tls_out_limit) {
                more_fragments = 1;
                len = data->tls_out_limit;
                wpa_printf(MSG_DEBUG, "SSL: sending %lu bytes, more fragments "
                           "will follow", (unsigned long) len);
        } else
                more_fragments = 0;

        length_included = data->tls_out_pos == 0 &&
                (data->tls_out_len > data->tls_out_limit ||
                 data->include_tls_length);
        if (!length_included &&
            eap_type == EAP_TYPE_PEAP && peap_version == 0 &&
            !tls_connection_established(data->eap->ssl_ctx, data->conn)) {
                /*
                 * Windows Server 2008 NPS really wants to have the TLS Message
                 * length included in phase 0 even for unfragmented frames or
                 * it will get very confused with Compound MAC calculation and
                 * Outer TLVs.
                 */
                length_included = 1;
        }

        *out_data = eap_msg_alloc(EAP_VENDOR_IETF, eap_type,
                                  1 + length_included * 4 + len,
                                  EAP_CODE_RESPONSE, id);
        if (*out_data == NULL)
                return -1;

        flags = wpabuf_put(*out_data, 1);
        *flags = peap_version;
        if (more_fragments)
                *flags |= EAP_TLS_FLAGS_MORE_FRAGMENTS;
        if (length_included) {
                *flags |= EAP_TLS_FLAGS_LENGTH_INCLUDED;
                wpabuf_put_be32(*out_data, data->tls_out_len);
        }

        wpabuf_put_data(*out_data, &data->tls_out[data->tls_out_pos], len);
        data->tls_out_pos += len;

        if (!more_fragments)
                eap_peer_tls_reset_output(data);

        return ret;
}


/**
 * eap_peer_tls_process_helper - Process TLS handshake message
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
 * @peap_version: Version number for EAP-PEAP  TLS
 * @id: EAP identifier for the response
 * @in_data: Message received from the server
 * @in_len: Length of in_data
 * @out_data: Buffer for returning a pointer to the response message
 * Returns: 0 on success, 1 if more input data is needed, 2 if application data
 * is available, or -1 on failure
 *
 * This function can be used to process TLS handshake messages. It reassembles
 * the received fragments and uses a TLS library to process the messages. The
 * response data from the TLS library is fragmented to suitable output messages
 * that the caller can send out.
 *
 * out_data is used to return the response message if the return value of this
 * function is 0, 2, or -1. In case of failure, the message is likely a TLS
 * alarm message. The caller is responsible for freeing the allocated buffer if
 * *out_data is not %NULL.
 *
 * This function is called for each received TLS message during the TLS
 * handshake after eap_peer_tls_process_init() call and possible processing of
 * TLS Flags field. Once the handshake has been completed, i.e., when
 * tls_connection_established() returns 1, EAP method specific decrypting of
 * the tunneled data is used.
 */
int eap_peer_tls_process_helper(struct eap_sm *sm, struct eap_ssl_data *data,
                                EapType eap_type, int peap_version,
                                u8 id, const u8 *in_data, size_t in_len,
                                struct wpabuf **out_data)
{
        int ret = 0;

        *out_data = NULL;

        if (data->tls_out_len > 0 && in_len > 0) {
                wpa_printf(MSG_DEBUG, "SSL: Received non-ACK when output "
                           "fragments are waiting to be sent out");
                return -1;
        }

        if (data->tls_out_len == 0) {
                /*
                 * No more data to send out - expect to receive more data from
                 * the AS.
                 */
                int res = eap_tls_process_input(sm, data, in_data, in_len,
                                                out_data);
                if (res) {
                        /*
                         * Input processing failed (res = -1) or more data is
                         * needed (res = 1).
                         */
                        return res;
                }

                /*
                 * The incoming message has been reassembled and processed. The
                 * response was allocated into data->tls_out buffer.
                 */
        }

        if (data->tls_out == NULL) {
                /*
                 * No outgoing fragments remaining from the previous message
                 * and no new message generated. This indicates an error in TLS
                 * processing.
                 */
                eap_peer_tls_reset_output(data);
                return -1;
        }

        if (tls_connection_get_failed(sm->ssl_ctx, data->conn)) {
                /* TLS processing has failed - return error */
                wpa_printf(MSG_DEBUG, "SSL: Failed - tls_out available to "
                           "report error");
                ret = -1;
                /* TODO: clean pin if engine used? */
        }

        if (data->tls_out_len == 0) {
                /*
                 * TLS negotiation should now be complete since all other cases
                 * needing more data should have been caught above based on
                 * the TLS Message Length field.
                 */
                wpa_printf(MSG_DEBUG, "SSL: No data to be sent out");
                os_free(data->tls_out);
                data->tls_out = NULL;
                return 1;
        }

        /* Send the pending message (in fragments, if needed). */
        return eap_tls_process_output(data, eap_type, peap_version, id, ret,
                                      out_data);
}


/**
 * eap_peer_tls_build_ack - Build a TLS ACK frame
 * @id: EAP identifier for the response
 * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
 * @peap_version: Version number for EAP-PEAP  TLS
 * Returns: Pointer to the allocated ACK frame or %NULL on failure
 */
struct wpabuf * eap_peer_tls_build_ack(u8 id, EapType eap_type,
                                       int peap_version)
{
        struct wpabuf *resp;

        resp = eap_msg_alloc(EAP_VENDOR_IETF, eap_type, 1, EAP_CODE_RESPONSE,
                             id);
        if (resp == NULL)
                return NULL;
        wpa_printf(MSG_DEBUG, "SSL: Building ACK (type=%d id=%d ver=%d)",
                   (int) eap_type, id, peap_version);
        wpabuf_put_u8(resp, peap_version); /* Flags */
        return resp;
}


/**
 * eap_peer_tls_reauth_init - Re-initialize shared TLS for session resumption
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * Returns: 0 on success, -1 on failure
 */
int eap_peer_tls_reauth_init(struct eap_sm *sm, struct eap_ssl_data *data)
{
        eap_peer_tls_reset_input(data);
        eap_peer_tls_reset_output(data);
        return tls_connection_shutdown(sm->ssl_ctx, data->conn);
}


/**
 * eap_peer_tls_status - Get TLS status
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * @buf: Buffer for status information
 * @buflen: Maximum buffer length
 * @verbose: Whether to include verbose status information
 * Returns: Number of bytes written to buf.
 */
int eap_peer_tls_status(struct eap_sm *sm, struct eap_ssl_data *data,
                        char *buf, size_t buflen, int verbose)
{
        char name[128];
        int len = 0, ret;

        if (tls_get_cipher(sm->ssl_ctx, data->conn, name, sizeof(name)) == 0) {
                ret = os_snprintf(buf + len, buflen - len,
                                  "EAP TLS cipher=%s\n", name);
                if (ret < 0 || (size_t) ret >= buflen - len)
                        return len;
                len += ret;
        }

        return len;
}


/**
 * eap_peer_tls_process_init - Initial validation/processing of EAP requests
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
 * @ret: Return values from EAP request validation and processing
 * @reqData: EAP request to be processed (eapReqData)
 * @len: Buffer for returning length of the remaining payload
 * @flags: Buffer for returning TLS flags
 * Returns: Pointer to payload after TLS flags and length or %NULL on failure
 *
 * This function validates the EAP header and processes the optional TLS
 * Message Length field. If this is the first fragment of a TLS message, the
 * TLS reassembly code is initialized to receive the indicated number of bytes.
 *
 * EAP-TLS, EAP-PEAP, EAP-TTLS, and EAP-FAST methods are expected to use this
 * function as the first step in processing received messages. They will need
 * to process the flags (apart from Message Length Included) that are returned
 * through the flags pointer and the message payload that will be returned (and
 * the length is returned through the len pointer). Return values (ret) are set
 * for continuation of EAP method processing. The caller is responsible for
 * setting these to indicate completion (either success or failure) based on
 * the authentication result.
 */
const u8 * eap_peer_tls_process_init(struct eap_sm *sm,
                                     struct eap_ssl_data *data,
                                     EapType eap_type,
                                     struct eap_method_ret *ret,
                                     const struct wpabuf *reqData,
                                     size_t *len, u8 *flags)
{
        const u8 *pos;
        size_t left;
        unsigned int tls_msg_len;

        if (tls_get_errors(sm->ssl_ctx)) {
                wpa_printf(MSG_INFO, "SSL: TLS errors detected");
                ret->ignore = TRUE;
                return NULL;
        }

        pos = eap_hdr_validate(EAP_VENDOR_IETF, eap_type, reqData, &left);
        if (pos == NULL) {
                ret->ignore = TRUE;
                return NULL;
        }
        if (left == 0) {
                wpa_printf(MSG_DEBUG, "SSL: Invalid TLS message: no Flags "
                           "octet included");
                if (!sm->workaround) {
                        ret->ignore = TRUE;
                        return NULL;
                }

                wpa_printf(MSG_DEBUG, "SSL: Workaround - assume no Flags "
                           "indicates ACK frame");
                *flags = 0;
        } else {
                *flags = *pos++;
                left--;
        }
        wpa_printf(MSG_DEBUG, "SSL: Received packet(len=%lu) - "
                   "Flags 0x%02x", (unsigned long) wpabuf_len(reqData),
                   *flags);
        if (*flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) {
                if (left < 4) {
                        wpa_printf(MSG_INFO, "SSL: Short frame with TLS "
                                   "length");
                        ret->ignore = TRUE;
                        return NULL;
                }
                tls_msg_len = WPA_GET_BE32(pos);
                wpa_printf(MSG_DEBUG, "SSL: TLS Message Length: %d",
                           tls_msg_len);
                if (data->tls_in_left == 0) {
                        data->tls_in_total = tls_msg_len;
                        data->tls_in_left = tls_msg_len;
                        os_free(data->tls_in);
                        data->tls_in = NULL;
                        data->tls_in_len = 0;
                }
                pos += 4;
                left -= 4;
        }

        ret->ignore = FALSE;
        ret->methodState = METHOD_MAY_CONT;
        ret->decision = DECISION_FAIL;
        ret->allowNotifications = TRUE;

        *len = left;
        return pos;
}


/**
 * eap_peer_tls_reset_input - Reset input buffers
 * @data: Data for TLS processing
 *
 * This function frees any allocated memory for input buffers and resets input
 * state.
 */
void eap_peer_tls_reset_input(struct eap_ssl_data *data)
{
        data->tls_in_left = data->tls_in_total = data->tls_in_len = 0;
        os_free(data->tls_in);
        data->tls_in = NULL;
}


/**
 * eap_peer_tls_reset_output - Reset output buffers
 * @data: Data for TLS processing
 *
 * This function frees any allocated memory for output buffers and resets
 * output state.
 */
void eap_peer_tls_reset_output(struct eap_ssl_data *data)
{
        data->tls_out_len = 0;
        data->tls_out_pos = 0;
        os_free(data->tls_out);
        data->tls_out = NULL;
}


/**
 * eap_peer_tls_decrypt - Decrypt received phase 2 TLS message
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * @in_data: Message received from the server
 * @in_decrypted: Buffer for returning a pointer to the decrypted message
 * Returns: 0 on success, 1 if more input data is needed, or -1 on failure
 */
int eap_peer_tls_decrypt(struct eap_sm *sm, struct eap_ssl_data *data,
                         const struct wpabuf *in_data,
                         struct wpabuf **in_decrypted)
{
        int res;
        const u8 *msg;
        size_t msg_len, buf_len;
        int need_more_input;

        msg = eap_peer_tls_data_reassemble(data, wpabuf_head(in_data),
                                           wpabuf_len(in_data), &msg_len,
                                           &need_more_input);
        if (msg == NULL)
                return need_more_input ? 1 : -1;

        buf_len = wpabuf_len(in_data);
        if (data->tls_in_total > buf_len)
                buf_len = data->tls_in_total;
        /*
         * Even though we try to disable TLS compression, it is possible that
         * this cannot be done with all TLS libraries. Add extra buffer space
         * to handle the possibility of the decrypted data being longer than
         * input data.
         */
        buf_len += 500;
        buf_len *= 3;
        *in_decrypted = wpabuf_alloc(buf_len ? buf_len : 1);
        if (*in_decrypted == NULL) {
                eap_peer_tls_reset_input(data);
                wpa_printf(MSG_WARNING, "SSL: Failed to allocate memory for "
                           "decryption");
                return -1;
        }

        res = tls_connection_decrypt(sm->ssl_ctx, data->conn, msg, msg_len,
                                     wpabuf_mhead(*in_decrypted), buf_len);
        eap_peer_tls_reset_input(data);
        if (res < 0) {
                wpa_printf(MSG_INFO, "SSL: Failed to decrypt Phase 2 data");
                return -1;
        }
        wpabuf_put(*in_decrypted, res);
        return 0;
}


/**
 * eap_peer_tls_encrypt - Encrypt phase 2 TLS message
 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
 * @data: Data for TLS processing
 * @eap_type: EAP type (EAP_TYPE_TLS, EAP_TYPE_PEAP, ...)
 * @peap_version: Version number for EAP-PEAP  TLS
 * @id: EAP identifier for the response
 * @in_data: Plaintext phase 2 data to encrypt or %NULL to continue fragments
 * @out_data: Buffer for returning a pointer to the encrypted response message
 * Returns: 0 on success, -1 on failure
 */
int eap_peer_tls_encrypt(struct eap_sm *sm, struct eap_ssl_data *data,
                         EapType eap_type, int peap_version, u8 id,
                         const struct wpabuf *in_data,
                         struct wpabuf **out_data)
{
        int res;
        size_t len;

        if (in_data) {
                eap_peer_tls_reset_output(data);
                len = wpabuf_len(in_data) + 300;
                data->tls_out = os_malloc(len);
                if (data->tls_out == NULL)
                        return -1;

                res = tls_connection_encrypt(sm->ssl_ctx, data->conn,
                                             wpabuf_head(in_data),
                                             wpabuf_len(in_data),
                                             data->tls_out, len);
                if (res < 0) {
                        wpa_printf(MSG_INFO, "SSL: Failed to encrypt Phase 2 "
                                   "data (in_len=%lu)",
                                   (unsigned long) wpabuf_len(in_data));
                        eap_peer_tls_reset_output(data);
                        return -1;
                }

                data->tls_out_len = res;
        }

        return eap_tls_process_output(data, eap_type, peap_version, id, 0,
                                      out_data);
}


/**
 * eap_peer_select_phase2_methods - Select phase 2 EAP method
 * @config: Pointer to the network configuration
 * @prefix: 'phase2' configuration prefix, e.g., "auth="
 * @types: Buffer for returning allocated list of allowed EAP methods
 * @num_types: Buffer for returning number of allocated EAP methods
 * Returns: 0 on success, -1 on failure
 *
 * This function is used to parse EAP method list and select allowed methods
 * for Phase2 authentication.
 */
int eap_peer_select_phase2_methods(struct eap_peer_config *config,
                                   const char *prefix,
                                   struct eap_method_type **types,
                                   size_t *num_types)
{
        char *start, *pos, *buf;
        struct eap_method_type *methods = NULL, *_methods;
        u8 method;
        size_t num_methods = 0, prefix_len;

        if (config == NULL || config->phase2 == NULL)
                goto get_defaults;

        start = buf = os_strdup(config->phase2);
        if (buf == NULL)
                return -1;

        prefix_len = os_strlen(prefix);

        while (start && *start != '\0') {
                int vendor;
                pos = os_strstr(start, prefix);
                if (pos == NULL)
                        break;
                if (start != pos && *(pos - 1) != ' ') {
                        start = pos + prefix_len;
                        continue;
                }

                start = pos + prefix_len;
                pos = os_strchr(start, ' ');
                if (pos)
                        *pos++ = '\0';
                method = eap_get_phase2_type(start, &vendor);
                if (vendor == EAP_VENDOR_IETF && method == EAP_TYPE_NONE) {
                        wpa_printf(MSG_ERROR, "TLS: Unsupported Phase2 EAP "
                                   "method '%s'", start);
                } else {
                        num_methods++;
                        _methods = os_realloc(methods,
                                              num_methods * sizeof(*methods));
                        if (_methods == NULL) {
                                os_free(methods);
                                os_free(buf);
                                return -1;
                        }
                        methods = _methods;
                        methods[num_methods - 1].vendor = vendor;
                        methods[num_methods - 1].method = method;
                }

                start = pos;
        }

        os_free(buf);

get_defaults:
        if (methods == NULL)
                methods = eap_get_phase2_types(config, &num_methods);

        if (methods == NULL) {
                wpa_printf(MSG_ERROR, "TLS: No Phase2 EAP methods available");
                return -1;
        }
        wpa_hexdump(MSG_DEBUG, "TLS: Phase2 EAP types",
                    (u8 *) methods,
                    num_methods * sizeof(struct eap_method_type));

        *types = methods;
        *num_types = num_methods;

        return 0;
}


/**
 * eap_peer_tls_phase2_nak - Generate EAP-Nak for Phase 2
 * @types: Buffer for returning allocated list of allowed EAP methods
 * @num_types: Buffer for returning number of allocated EAP methods
 * @hdr: EAP-Request header (and the following EAP type octet)
 * @resp: Buffer for returning the EAP-Nak message
 * Returns: 0 on success, -1 on failure
 */
int eap_peer_tls_phase2_nak(struct eap_method_type *types, size_t num_types,
                            struct eap_hdr *hdr, struct wpabuf **resp)
{
        u8 *pos = (u8 *) (hdr + 1);
        size_t i;

        /* TODO: add support for expanded Nak */
        wpa_printf(MSG_DEBUG, "TLS: Phase 2 Request: Nak type=%d", *pos);
        wpa_hexdump(MSG_DEBUG, "TLS: Allowed Phase2 EAP types",
                    (u8 *) types, num_types * sizeof(struct eap_method_type));
        *resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_NAK, num_types,
                              EAP_CODE_RESPONSE, hdr->identifier);
        if (*resp == NULL)
                return -1;

        for (i = 0; i < num_types; i++) {
                if (types[i].vendor == EAP_VENDOR_IETF &&
                    types[i].method < 256)
                        wpabuf_put_u8(*resp, types[i].method);
        }

        eap_update_len(*resp);

        return 0;
}
